Elenion's coherent and fibre-to-the-server plans

• Elenion’s coherent chip - an integrated modulator-receiver assembly - is now generally available. 
• The company has a silicon photonics design library that includes over 1,000 elements. 
• Elenion is also developing an optical engine for client-side interfaces.

Elenion Technologies has given an update on its activities and strategy after announcing itself eight months ago. The silicon photonics-based specialist is backed by private equity firm, Marlin Equity Partners, which also owns systems vendor, Coriant. Elenion had already been active for two and a half years and shipping product when it emerged from its state of secrecy last December. 

Larry SchwerinElenion has since announced it is selling its telecom product, a coherent transceiver PIC, to Coriant and now other companies.

It has also progressed its optical engine design for the data centre that will soon be a product. Elenion has been working with Ethernet switch chip maker, Cavium, and data centre player, Microsoft, as part of its datacom work.

“We have moved forward,” says Larry Schwerin, the CEO of Elenion.

Coherent PIC

Elenion’s integrated modulator-receiver assembly is being used by Coriant for two CFP2 Analogue Coherent Optics (CFP2-ACO) modules as part of its Groove G30 platform.

The first is a short-reach CFP2-ACO for point-to-point 200-gigabit links that has a reach of at least 80km. The second is a high-performance CFP2-ACO that has a reach of up to 4,000km at 100 gigabits and 650km at 200 gigabits. 

Schwerin says the company is now selling the coherent PIC to “a lot of people”. In addition to the CFP2-ACO, there is the Digital Coherent Optics (DCO) pluggable market where the PIC and the coherent digital signal processor (DSP) are integrated within the module. Examples include the CFP-DCO and the smaller CFP2-DCO which is now being designed into new systems. ADVA Optical Networking is using the CFP2-DCO for its Teraflex, as is its acquisition target MRV with its 200-gigabit coherent muxponder. Infinera’s latest XTM II platforms also use the CFP2-DCO.

We have got a library that has well over 1,000 elements

Using silicon photonics benefits the cost and performance of the coherent design, says Schwerin. The cost benefit is a result of optical integration. “You can look at it as a highly simplified supply chain,” says Schwerin. Coupling the electronics close to the optics also optimises overall performance.  

Elenion is also targeting the line-card market for its coherent PIC. “This is one of the reasons why I wanted to stay out of the pluggable business,” says Schwerin. “There are a lot more customers out there if you stay out of pluggables because now you are selling an [optical] engine.”

The company is also developing a coherent PIC design that will support higher data rates such as 400- and 600-gigabit per lambda. “Without being too specific because we do remain stealthy, we have plans to support these applications,” says Schwerin.

Schwerin stresses that the real strength of the company is its design library used to develop its silicon photonics circuits. Elenion emerged out of a silicon photonics design-for-service company. “We have got a library that has well over 1,000 elements,” he says. Elenion says it can address custom design requests of companies using its design library.

Datacom

Elenion announced at the OFC show held in Los Angeles in March that it is working with Jabil AOC Technologies, a subsidiary of the manufacturing firm, Jabil Circuits. Elenion chose the contract manufacturer due to its ability to address both line-card and pluggable designs, the markets for its optical engines. 

The two firms have also been working at the chip level on such issues as fibre attach, coupling the laser and adding the associated electronics. “We are trying to make the interface as elegant and streamlined as possible,” says Schwerin. “We have got initiatives underway so that you don't need these complex arrangements.”

Schwerin highlights the disparity between the unit volumes needed for the telecom and datacom markets. According to forecasts from market research firms, the overall coherent market is expected to grow to 800,000 and 1 million units a year by 2020. In contrast, the interfaces used inside one large-scale data centre can be up to 2 million. “To achieve rapid manufacturing and yield, you have got to simplify the process,” he says.

This is what Elenion is tackling. If 1,000 die can be made on a single silicon wafer, and knowing the interface volumes required and the yields, the total number of wafer runs can be determined. And it is the overall time taken from starting a wafer to the finished transceiver PIC output that Elenion is looking to shorten, says the CEO.

We ran that demo from 7 AM to 2 AM every day of the show  

At OFC, Elenion hired a hotel suite near the convention centre to demonstrate its technologies to interested companies. One demonstration used its 25Gbps optical engine directly mounted on a Cavium QLogic network interface card (NIC) connecting a server to a high-capacity Cavium Xpliant Ethernet switch chip. The demo showed how 16 NICs could be connected to the switch chip for a total capacity of 400 gigabits. “No more direct-attached cables or active optical cables, literally fibre-to-the-server,” says Schwerin. “We ran that demo from 7 AM to 2 AM every day of the show.”   

Elenion’s on-board optics design was based on the emerging Consortium of On-Board Optics (COBO) standard. “The Microsoft folks, we work with them closely, so obviously what we are doing follows their intent,” says Schwerin.

The optical engine will also support 56Gbps links when used with four-level pulse-amplitude modulation (PAM-4) and the company is even eyeing 100Gbps interfaces. For now, Elenion’s datacom optical engine remains a technical platform but a product will soon follow.

The company’s datacom work is also benefiting its telecom designs. “The platform technology that we use for datacom has now found its way into the coherent programme, especially around the packaging,” says Schwerin. 

* The article was changed on July 25th to mention that Elenion's PIC is being used in two Coriant CFP-ACOs.